The present invention relates to a light emitting array module comprising one or more light emitting elements and, more particularly, to a transmission light emitting array module and a control method of the same for use in an apparatus for transmitting bidirectional burst signals.
An optical parallel transmission system is excellent in transmission speed, transmission distance and EMI-proof characteristic (resistibility to the influence of EMI) in comparison with an electric parallel transmission system. Moreover, since the volume of the cable per se used as a transmission line can be extremely reduced, wide applications such as a computer interface are expected. A plurality of light sources are indispensable to the optical parallel transmission system. To reduce the size of the transmitting apparatus so as to cut down the cost, it is extremely preferable to utilize a light emitting array module that is formed by aligning a plurality of light emitting elements and optical fibers integrally in an array fashion.
As described in detail later, in a conventional light emitting array module, semiconductor lasers are aligned to obtain the optimum coupling on a substrate, and optical fibers are also aligned on the substrate at the same distance as that of the semiconductor lasers to be optically coupled to the semiconductor lasers. The optical fibers are coupled correspondingly to the semiconductor lasers, and thus are coupled to external optical transmission lines as they are. Therefore, there is a drawback such that, if the failure occurs in even one semiconductor laser, one of optical parallel signals is completely disabled.
The semiconductor laser scarcely degrades abruptly. Normally, the optical output of the semiconductor laser falls gradually. However, in the conventional light emitting array module, neither a monitoring function which monitors the deterioration of the semiconductor lasers nor a switching function which switches the failed semiconductor laser into a spare semiconductor laser is provided. Therefore, since the extremely deteriorated semiconductor laser cannot be detected in advance, there is a possibility that the communication is suddenly disabled. In addition, there is another drawback such that the communication must be interrupted for a long time since it takes a lot of time to exchange the failed semiconductor laser with a new one.